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// $Id: channel.hpp 5188 2012-08-30 00:31:31Z dub $
/*
Copyright (c) 2007-2012, Trustees of The Leland Stanford Junior University
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this
list of conditions and the following disclaimer in the documentation and/or
other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
//////////////////////////////////////////////////////////////////////
//
// File Name: channel.hpp
//
// The Channel models a generic channel with a multi-cycle
// transmission delay. The channel latency can be specified as
// an integer number of simulator cycles.
//
/////
#ifndef _CHANNEL_HPP
#define _CHANNEL_HPP
#include <queue>
#include <cassert>
#include "globals.hpp"
#include "module.hpp"
#include "timed_module.hpp"
using namespace std;
template<typename T>
class Channel : public TimedModule {
public:
Channel(Module * parent, string const & name);
virtual ~Channel() {}
// Physical Parameters
void SetLatency(int cycles);
int GetLatency() const { return _delay ; }
// Send data
virtual void Send(T * data);
// Receive data
virtual T * Receive();
virtual void ReadInputs();
virtual void Evaluate() {}
virtual void WriteOutputs();
protected:
int _delay;
T * _input;
T * _output;
queue<pair<int, T *> > _wait_queue;
};
template<typename T>
Channel<T>::Channel(Module * parent, string const & name)
: TimedModule(parent, name), _delay(1), _input(0), _output(0) {
}
template<typename T>
void Channel<T>::SetLatency(int cycles) {
if(cycles <= 0) {
Error("Channel must have positive delay.");
}
_delay = cycles ;
}
template<typename T>
void Channel<T>::Send(T * data) {
_input = data;
}
template<typename T>
T * Channel<T>::Receive() {
return _output;
}
template<typename T>
void Channel<T>::ReadInputs() {
if(_input) {
_wait_queue.push(make_pair(GetSimTime() + _delay - 1, _input));
_input = 0;
}
}
template<typename T>
void Channel<T>::WriteOutputs() {
_output = 0;
if(_wait_queue.empty()) {
return;
}
pair<int, T *> const & item = _wait_queue.front();
int const & time = item.first;
if(GetSimTime() < time) {
return;
}
assert(GetSimTime() == time);
_output = item.second;
assert(_output);
_wait_queue.pop();
}
#endif
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